Rename rbos → redbear everywhere, add redbear-info system tool

Replace all 'rbos'/'RBOS' references with 'redbear'/'Red Bear OS'
across the build system, scripts, docs, and configs. Renamed files:
  rbos.ipxe → redbear.ipxe
  assets/rbos-icon.png → assets/redbear-icon.png
  recipes/system/rbos-info → recipes/system/redbear-info

Added redbear-info: a system tool that enumerates all Red Bear OS
custom components, checks runtime availability via scheme paths and
binary presence, and prints status/test info. Supports --verbose,
--json, and --test output modes. Zero external dependencies.

local/scripts/test-amd-gpu.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 # Test AMD GPU driver on Red Bear OS
-# Run this inside RBOS (or via QEMU serial console)
+# Run this inside Red Bear OS (or via QEMU serial console)
 set -euo pipefail
 
 echo "=== AMD GPU Driver Test ==="